013 performance of coriolis meters gas flow - Cesar Delgado

Vista previa del material en texto

PERFORMANCE OF CORIOLIS METERS IN GAS FLOW 
 
Dr David G. Stewart, NEL, East Kilbride, Glasgow, UK 
 
 
Introduction 
 
Coriolis meters are used widely in the oil and process industry for metering liquids. They offer 
many advantages in terms of accuracy, repeatability, and relatively low sensitivity to installation effects. 
Coriolis meters also have the advantage that they measure the mass flowrate directly, removing the need 
for density calculations and corrections. 
Recent advances in Coriolis meter technology have meant that their use in gas flow measurement 
has been on the increase. Indeed, high accuracy direct measurement of the mass flow of gases is now 
possible. This has been reflected in interest at ISO level where TC30/SC12 are currently drafting a 
Standard on Coriolis meters for gas applications. 
Most manufacturers will calibrate these meters (intended for gas) in water and simply quote a 
larger uncertainty for gas measurement. However, prior to this project starting there was very little 
independent data to support this approach. This work was designed to investigate the performance of 
Coriolis meters in gas. This would provide completely independent data from which conclusions can be 
drawn regarding their use in gas, and also whether a water calibration is sufficient. 
The work featured in this paper was undertaken as part of the 1999 – 2002 Flow Programme. 
The Flow Programme is funded by the UK government’s Department of Trade and Industry (DTI), 
within their National Measurement System Directorate. The Flow Programme is designed to undertake 
generic research in flow measurement and closely related topics. 
In this paper results are presented from tests on two Coriolis meters from different 
manufacturers. The manufacturers in question have requested that at this stage the data be presented 
anonymously, until the project has been completed. The estimated completion date for this project is 
May 2002. 
 
Objectives 
 
The principal aim of this project was to provide independent and reliable data on the performance of 
Coriolis meters in gas. In doing so there were several particular areas highlighted for investigation, 
namely: 
 
• investigate performance at different pressures/densities, 
• test for zero stability, 
• investigate behaviour if the flowrate becomes limited by choking, 
• investigate whether or not the performance varies with the location of the reference sonic nozzle. 
 
Test Method 
 
Water calibration 
Before undertaking any gas tests, the meters were calibrated in water to give a baseline 
performance test against which the gas tests could be compared. 
 
 
 1 
Gas tests 
The meters were tested at three pressures, 10 bar, 30 bar, and 50 bar. The range of flowrates 
would vary for each meter but the lowest would be around 50g/s, and the maximum between 0.6 kg/s 
and 1.0 kg/s depending on meter size and design. Sonic (critical flow) nozzles would be used as the 
reference meters. 
 
Zero Stability 
Coriolis meters can be affected by zero stability problems, where the meter indicates a flowrate 
even though there is no flow through the meter. During the gas tests the meter reading was observed 
whenever the flow was closed off. 
The rig was fully assembled and the Coriolis meter clamped firmly on either side. The line was 
closed off at ambient pressure by a valve upstream and downstream of the meter and the meter zeroed. 
The meter was tested at the three pressures. 
Any zero drift with pressure was noted and taken into account when calculating results. If there 
was significant zero drift at any pressure, the meter was re-tested after being zeroed at the corresponding 
pressure. 
 
Choking 
Before these tests began, there was some expectation that the meter performance would be 
affected by choking. At high flowrates it was thought that the high velocities and large pressure drops 
through the meter would create a lot of noise in the signal, making it difficult for the meter to distinguish 
the flow signal. 
To investigate the occurrence and effect of choking, the meter was taken to the maximum 
flowrate that could be achieved at each pressure. When testing with the nozzle downstream, the 
flowrate is controlled by a valve between the meter and the nozzle. As the valve is opened the pressure 
at the nozzle increases and the mass flowrate increases accordingly. If there comes a point where further 
opening of the valve has no influence on the pressure at the nozzle and the mass flowrate then the meter 
has choked, and the mass flowrate is the maximum that can be achieved for the given upstream pressure 
and temperature at the meter. 
Each Coriolis meter was taken up to its maximum mass flowrate at each pressure until the onset 
of choking. If choking occurred, the meter was tested at flowrates near to the choked flowrate to check 
for any instability. 
 
Reverse flow 
At high gas flows there is a temperature drop across the meter due to the pressure drop across the 
meter. It is possible that the location of the temperature sensor, and hence the value used in the meter, 
may have some influence on the meter performance. 
The meters were tested for any temperature effects by testing with flow in both directions at high 
flowrates, where the temperature drop across the meter would be largest. 
The reverse flow tests will also provide information on the general performance in reverse 
orientation over a wider range of flowrates. This information will be used to examine whether claims of 
bi-directional flow are justified. 
 
Effect of Sonic Nozzles 
For the initial tests the nozzle was located downstream of the meter. Where possible, reference 
sonic nozzles were positioned upstream as well as downstream and, when located upstream, the distance 
between the nozzle and the Coriolis meter was varied. This would show whether any of the Coriolis 
meters are affected by any acoustic noise produced by a sonic nozzle. 
 2 
 
Test facilities and meters 
 
NEL Water flow facility 
The NEL water flow facility used to calibrate the two Coriolis meters is a small water flow 
facility, capable of flowrates in the range 0.003 kg/s to 0.85 kg/s. This rig is suited for flowrates in the 
range of the two meters tested. 
 
This rig is a UK primary standard gravimetric facility, and the uncertainty in mass flowrate is estimated 
to be 0.12% or better. This expanded uncertainty is based on a standard uncertainty multiplied by a 
coverage factor k=2, providing a level of confidence of approximately 95%. The uncertainty evaluation 
has been carried out in accordance with UKAS requirements. 
 
NEL High-pressure air test facility 
The NEL high-pressure air test facility is known as a blow-down facility due to the fact that 
high-pressure air is stored in a vessel, and is discharged through the reference meter and test line to 
atmosphere. The compressors that fill the vessel can provide a certain flowrate without depleting the 
vessel. However, above this flowrate, air from the storage vessel is used, and the pressure in this vessel 
falls with a consequent restriction on the available run time. The maximum test time in any given case 
depends on the mass flowrate and the pressure required at the inlet to the test line. 
Two sets of dome loaders (pressure regulating valves) are used to control the pressure at the inlet 
to the test line. The mass flowrate is controlled by either varying the pressure at the reference nozzle in 
the case of the nozzle being upstream of the test device, or adjusting a flow control valve between the 
test meter and the reference nozzle in the case of the nozzle being downstream of the test meter. 
The uncertainty in mass flowrate through the reference sonic nozzle is estimated to be 0.21% or 
better. This expanded uncertainty is based on a standard uncertainty multiplied by a coverage factor k=2, 
providing a level of confidence of approximately 95%. The uncertainty evaluation hasbeen carried out 
in accordance with UKAS requirements. 
 
Test Meters 
 The two test meters shall be referred to as Meter A and Meter B. Both meters were nominal ½” 
meters. This size was selected to ensure that we could test up at flowrates up to choked conditions 
without compromising run times in the test rig. In both cases the meter pulsed output was used to 
determine meter indicated flow. 
 
Meter A results and discussion 
 
Water results 
 Meter A was tested in the water facility up to the maximum flowrate that could be achieved with 
this particular meter installed. This maximum flowrate turned out to be 747 g/s. It was recognized from 
discussions with the manufacturer that the maximum gas flow rate would probably be greater than this. 
As the meter shows a linear performance and the expected performance of this type of meter would 
allow extrapolation it was decided not to continue the test on one of the larger water lines to cover the 
remaining flow range. 
The results for the water calibration are shown in Fig. A.1. It can be seen that with the exception 
of one point, at around 570 g/s, all points are well within the specified meter accuracy in liquid service 
(represented by the dotted lines). The repeatability is also very good across the range tested. 
 3 
The linearity is good across most of the range with all points above 200 g/s lying between 0.03% 
and 0.08% (with the one exception at 0.12%). The results fall off slightly at the bottom end, yet at 10 
g/s the error is only just below -0.2%. This flowrate corresponds to a turn down ratio of 75:1. 
This water calibration is a good indication of the performance of this meter in liquid, and as such 
provides a good baseline against which the performance in gas can be judged. 
 
Gas results 
 The 10 bar results are shown in Figure A.2. It can be seen that the meter error steadily rises from 
around 0.4% at a mass flowrate of 60 g/s to around 0.6% to 0.7% at the maximum flowrate of just over 
200 g/s. The dotted lines show the specified meter accuracy in gas service. At 10 bar, the meter 
performs within the specified uncertainty up to a flowrate of around 120 g/s, but with the error 
increasing with flowrate the meter error exceeds the specified uncertainty for flowrates above this 
(maximum flow approximately 200 g/s at 10 bar). Above 140 g/s the mean error is approximately 0.6% 
with all points lying within 0.1% of this mean. 
 The results from the 30 bar tests are shown in Figure A.3. At 30 bar, the meter performs better 
than at 10 bar. All data points are within the specified accuracy. Up 230 g/s the meter was very 
repeatable and the error reduced from 0.4% at 50 g/s to 0.23% at 230 g/s. Above 230 g/s (maximum 
flow approximately 580 g/s at 30 bar) the increases slightly and the repeatability is slightly poorer. 
Above 230 g/s, all data points lie in the band 0.2% to 0.5% with the mean error approximately 0.35%. 
 The results from the 50 bar test are shown in Figure A.4. At 50 bar, the meter performs better 
than in the 10 bar or 30 bar tests. All data points are comfortably within the specified meter accuracy in 
gas service. The repeatability is also improved at 50 bar compared with 10 bar and 30 bar. The error 
steadily decreases from 0.3% at 60 g/s down to just above 0.0% at approximately 380 g/s. Above this 
flow (maximum flow approximately 950 g/s at 50 bar) the error lies between 0.0% and 0.2% with the 
mean around 0.15%. The repeatability remains reasonably good, even at high flowrates. 
 
Zero stability 
The meter was initially zeroed before the first gas tests with the line closed at ambient pressure 
by a valve either side of the meter. The zero was observed to be very stable at this condition. The line 
was then pressurized to 10 bar and the line was closed once again and allowed to stabilize for a few 
minutes. The zero showed no drift at this increased pressure and was very stable, only fluctuating 
occasionally within the range –0.04 g/s to 0.04 g/s (the resolution of the meter was 0.01 g/s). 
Consequently there was no need to re-zero the meter before performing the 10 bar tests. 
The line was then pressurized to 30 bar, then closed and allowed to stabilize for a few minutes. 
The zero showed no drift this time either, being very stable again, only fluctuating very slightly within 
the same range as at 10 bar. Consequently there was no need to re-zero the meter before performing the 
30 bar tests. 
Finally, the line was pressurized to 50 bar, then closed and allowed to settle for a few minutes. 
Once again, the zero showed no drift, only fluctuating slightly as before at 10 bar and 30 bar. 
Consequently there was no need to re-zero the meter before performing the 50 bar tests. 
These initial tests at 10 bar, 30 bar, and 50 bar with the nozzle downstream of the meter were 
carried out over a period of several days. Consequently the process of pressurizing the line, checking 
the zero, testing, and then venting the line was undertaken several times at each pressure with no 
significant effect on the meter performance. This is illustrated in Figures. A.2 to A.4, which show 
results from different test runs at each of the three test pressures. 
 
 4 
Choking 
Figures A.2 to A.4 show the results at choked conditions, which are essentially the highest flow 
points at each pressure. At all three pressure it can be seen that there is an increase in the scatter of the 
results at upper flow range. However, the meter continued to function and output a measurement at the 
choked flow conditions and there is no significant deterioration in performance at choked flow. 
 
Reverse flow 
 The results from the reverse flow tests are presented in Figures A.5 to A.7, for the 10 bar, 30 bar 
and 50 bar results respectively. Tests were carried out only at the higher end of the flowrate range at 
each pressure, as it is here that any difference in performance due to the temperature difference across 
the meter would be noticeable. 
It is clear that there is no significant difference in the performance of the meter in the reverse 
orientation at 10 bar. The reverse flow results lie largely within the scatter of the original test results. 
The same is true at both 30 bar and 50 bar. At 30 bar there are a few points at flowrates of just under 
500 g/s that lie below the original test results, however, the difference is less than 0.2% and could well 
be a result of the scatter at higher flowrates. 
These tests show that the meter performance is almost identical in the reverse orientation across 
the flow range at all three pressures tested. It appears from this that either the location of the 
temperature sensor does not have a significant influence on the meter performance, or the temperature 
drop across the meter is not significant enough to cause an effect. In practical terms, however, the meter 
is not likely to be used at such extreme flowrates and consequently temperature drops of this magnitude 
will not be encountered in industry. Therefore the meter could be used to measure in both directions 
with equal confidence in the measurement. 
 
Effect of Sonic Nozzles 
This section details the tests performed with the reference nozzle upstream of the nozzle to 
investigate any possible interference, and describes the results obtained. It was decided to do these tests 
with the nozzle as close to the meter as physically possible, and then, if there was any significant change 
in the meter performance compared with the original tests, to move the nozzle further upstream away 
from the meter. 
Initially, it was assumed that if there was going to be any interference from the nozzle then it 
would most likely occur when the nozzle was as close upstream as possible to the meter. The design of 
the nozzle package dictates that the minimum distance that could be achieved between the nozzle and 
the meter was 1.5m. 
Following these tests, the nozzle was moved further away fromthe meter under test to 
investigate whether any effect would change with distance. Accordingly the nozzle was installed 5.5m 
upstream of the meter. The results from the tests with the nozzle upstream of the meter are shown in 
Figures A.8 to A.10 for the 10 bar, 30 bar and 50 bar results respectively. 
At the lower flowrates in the 10 bar tests, below 150 g/s, there is a very slight reduction in the 
meter reading with the nozzle 1.5m upstream, less than 0.2%. At the higher flowrates, above 150 g/s, 
there is no noticeable effect from having the nozzle close upstream of the meter. With the nozzle 5.5m 
upstream of the meter, there is no significant difference between these results and those obtained with 
the nozzle downstream of the meter across the entire flow range tested. Two reference nozzles were 
used in these tests, one up to 150 g/s and one above 150 g/s. 
At 30 bar, as in the 10 bar test, there appears to be a slight reduction in the meter reading at the 
lower flowrates with the nozzle 1.5m upstream; this time below 350 g/s. In this case the difference is no 
greater than 0.1%, within the uncertainty of the reference mass flowrate. At higher flowrates, above 350 
g/s, there is no noticeable effect with the exception of the very highest flowrate, when the meter is 
 5 
choked. At this condition, there seems to be a slight reduction in the meter output, although in both this 
and the original test (with nozzle downstream) there is significant scatter in the results. With the nozzle 
5.5m upstream, it is clear that there is no significant difference between these results and those obtained 
with the nozzle downstream of the meter across the entire flow range tested. Three nozzles were used to 
cover the flow range in the 30 bar tests with the nozzle upstream. These nozzles covered the ranges 100 
g/s to 165 g/s, 180 g/s to 310 g/s, and 350 g/s to 580 g/s. 
The results from the 50 bar tests are shown below in Figure A.10. Due to the limitations in test 
times at high flowrates, it was not possible to do many tests at 50 bar with the nozzle upstream. With 
the nozzle 1.5m upstream, there appears to be a slight reduction in the meter reading, although the 
difference is around 0.1% – 0.15%, again within the uncertainty of the reference mass flowrate. With 
the nozzle 5.5m upstream, there is no significant difference compared with the nozzle downstream tests. 
Two nozzles were used in these tests, one for each of the points flowrates tested. 
Overall, it is clear that the meter is not significantly affected by the presence of a reference sonic 
nozzle close upstream. With the meter 1.5m upstream there was a slight reduction in the meter output at 
most conditions, between 0.1% and 0.2%. With the meter 5.5m upstream there was no significant 
difference from the nozzle downstream tests. 
 
Meter B results and discussion 
 
Water results 
 Meter B was tested in the water facility at flowrates from 25 g/s to just over 700 g/s. The results 
for the water calibration are shown in Fig. B.1. It can be seen that all points are well within the specified 
meter accuracy in liquid service (represented by the dotted lines). The repeatability is also very good 
across the range tested. The linearity is very good from 100 g/s upwards. 
This water calibration is a good indication of the performance of this meter in liquid, and as such 
provides a good baseline against which the performance in gas can be judged. 
 
Gas results 
 The 10 bar results are shown in Figure B.2. It can be seen that the meter error steadily decreases 
from around -0.1% at a mass flowrate of 40 g/s to around -0.6% at approximately 150 g/s. From 150 g/s 
to the maximum flow achieved through the meter, just over 190 g/s, the meter error rises steeply to 
between 0% and –0.2%. The dotted lines show the specified meter accuracy in gas service. At 10 bar, 
the meter performs within the specified uncertainty with the exception of a few points. The results do, 
however show an unusual trend. 
 The results from the 30 bar tests are shown in Figure B.3. At 30 bar, the meter performs in a 
very similar manner to that at 10 bar. Most data points are within the specified accuracy, with a few 
outside at the higher flow end. Again, however, the meter results display an unusual trend. 
 The results from the 50 bar test are shown in Figure B.4. At 50 bar, the meter performs in a very 
similar manner to that at 10 bar and 30 bar. Most data points are within the specified accuracy, with a 
few outside at the higher flow end. As at 10 bar and 30 bar, however, the meter results display a similar 
trend. 
 
Zero stability 
The process described for meter A above was also carried out for meter B. The meter was 
zeroed at atmospheric pressure and remained very steady at this pressure and at all three test pressures. 
There was no need to re-zero the meter at any time during the tests. 
The initial tests at 10 bar, 30 bar, and 50 bar with the nozzle downstream of the meter were 
carried out over a period of several days. As with meter A, the process of pressurizing the line, checking 
 6 
the zero, testing, and then venting the line was undertaken several times at each pressure with no 
significant effect on the meter performance. This is illustrated in Figures. B.2 to B.4, which show 
results from different test runs at each of the three test pressures. 
 
Choking 
Figures B.2 to B.4 show the results at high flowrates at each pressure. At all three pressures it 
can be seen that as the flowrate approaches the high flow end of the range the meter error starts to 
increase from approximately –0.6 to bewteen –0.4% and 0%. There is a significant increase in the 
scatter of the results as the flow approaches the maximum success. 
Choked flow was not actually achieved with meter B. The meter ceased to output a signal above 
the highest flowrates shown on Figures B.2 to B.4. It is known that the meter did not choke as the 
pressure at the outlet of the meter was still significantly higher than the pressure at the reference nozzle 
downstream of the meter. 
 
Reverse flow 
 The results from the reverse flow tests are presented in Figures B.5 to B.7, for the 10 bar, 30 bar 
and 50 bar results respectively. Tests were carried out only at the higher end of the flowrate range at 
each pressure, as it is here that any difference in performance due to the temperature difference across 
the meter would be noticeable. 
There is no significant difference in the performance of the meter in the reverse orientation at 10 
bar and 30 bar. The reverse flow results lie largely within the scatter of the original test results. At 50 
bar, however, the results at lower flowrates (less than 300 g/s) lie below the forward flow results by 
approximately 0.2%. At higher flows the results appear to be more in agreement with the forward flow 
tests, although the scatter in both sets makes it difficult to draw any conclusions. 
These tests show that the meter performance is similar in the reverse orientation across the flow 
range at 10 bar and 30 bar, but at 50 bar there appears to be an effect. It is unlikely that this effect is due 
to the location of the temperature sensor as this would be most noticeable at the higher flows. 
 
Effect of Sonic Nozzles 
Meter B was tested with the reference nozzle upstream in the same configurations as meter A, 
i.e. with the nozzle 1.5m and 5.5m upstream of the meter. The results from the tests with the nozzle 
upstream of the meter are shown in Figures B.8 to B.10 for the 10 bar, 30 bar and 50 bar results 
respectively. 
In the 10 bar tests, the results with the nozzle 1.5m upstream are significantly lower than the 
nozzle downstream tests at flowrates below 130 g/s. Above this flow, the results fall more in line with 
the nozzle downstream tests, albeit with significant scatter in both sets. When the nozzle was moved 
5.5m upstream of the meter, the results were actually worse thanat 1.5m. Across the flow range tested 
the results lie significantly below those with the nozzle 1.5m upstream, with many points outside the 
meter specification. 
At 30 bar the results from both sets of tests with the nozzle upstream lie significantly below the 
nozzle downstream tests. As at 10 bar, the results with the nozzle 5.5m upstream of the meter are 
slightly lower than those with the nozzle 1.5m upstream of the meter, and again the scatter is very large. 
As with meter A, due to the limitations in test times at high flowrates, it was not possible to do 
many tests at 50 bar with the nozzle upstream. However, at the two flowrates achieved it can be seen 
that the results lie significantly below the nozzle downstream tests. At 50 bar the results with the nozzle 
1.5m and 5.5m upstream of the meter are very close together. 
 7 
Overall, it is clear that meter B is significantly affected by the presence of a reference sonic 
nozzle close upstream. The meter output is lower by between 0.2% and 0.5%. This effect did not 
reduce as the nozzle was moved from 1.5m to 5.5m upstream of the meter. 
 
Conclusions 
 
Meter A 
 The initial water calibration showed that Meter A performed well within the meter specification 
and the performance was repeatable across the flow range tested. The gas results for Meter A were 
almost all within the meter specification with the exception of the higher flow end at 10 bar. The 
performance of Meter A improved with increasing pressure. This is an expected trend as at higher 
pressures, and hence higher gas density, there is more mass inside the meter to measure. 
 The zero stability of Meter A was very good throughout the test program; the meter did not have 
to be re-zeroed at any time. The zero was established at atmospheric pressure and did not drift at 
pressure up to 50 bar. 
 The meter did not appear to be affected by the onset of choking and continued to operate up to 
the maximum possible flow with only a slight increase in the scatter of the results. 
 Meter A performed in an almost identical manner in both forward and reverse flow directions. 
 Meter A was not seriously affected by the presence of a sonic nozzle upstream. Tests with the 
nozzle 1.5m upstream showed a slight decrease in the meter output, of the order of 0.1 to 0.2%. Moving 
the nozzle to 5.5m upstream eliminated this effect. 
 
Meter B 
 The initial water calibration showed that Meter B performed well within the meter specification 
and the performance was repeatable across the flow range tested. The gas results for Meter B were 
mostly within the meter specification with the exception of the higher flow points at each pressure. 
However, the results displayed an unusual trend with increasing flowrate, as shown in Figures B.2 to 
B.4. The overall performance of Meter B did not improve significantly with increasing pressure, 
although the repeatability did improve at the lower flowrates. 
 The zero stability of Meter B was very good throughout the test program; the meter did not have 
to be re-zeroed at any time. The zero was established at atmospheric pressure and did not drift at 
pressure up to 50 bar. 
 The meter appeared to be seriously affected by the onset of choking and failed to give a readout 
before the maximum possible flow was reached. 
 Meter B performed in an almost identical manner in both forward and reverse flow directions at 
10 and 30 bar, but lower flowrates at 50 bar showed some change in performance. 
 Meter B was significantly affected by the presence of a nozzle upstream. The performance did 
not improve when the distance between the nozzle and the meter was increased from 1.5m to 5.5m. 
 
 8 
APPENDIX A - METER A RESULTS 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700 800
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Figure A.1. Baseline water tests for meter A. (Dotted lines represent manufacturer’s meter 
specification.) 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 20 40 60 80 100 120 140 160 180 200
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Run 1
Run 2
Run 3
 
 
Figure A.2. Gas tests on meter A at 10 bar. Results shown from different test runs. (Dotted lines 
represent manufacturer’s meter specification.) 
 9 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600
Reference mas flowrate (g/s)
M
et
er
 e
rr
or
 (%
Run 1
Run 2
Run 3
 
Figure A.3. Gas tests on meter A at 30 bar. Results shown from different test runs. (Dotted lines 
represent manufacturer’s meter specification.) 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700 800 900 1000
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Run 1
Run 2
 
 
Figure A.4. Gas tests on meter A at 50 bar. Results shown from different test runs. (Dotted lines 
represent manufacturer’s meter specification.) 
 10 
 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 20 40 60 80 100 120 140 160 180 200
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Forward flow
Reverse flow
 
Figure A.5. Reverse flow gas tests on meter A at 10 bar. (Dotted lines represent manufacturer’s meter 
specification.) 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Forward flow
Reverse flow
 
Figure A.6. Reverse flow gas tests on meter A at 30 bar. (Dotted lines represent manufacturer’s meter 
specification.) 
 11 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700 800 900 1000
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Forward flow
Reverse flow
 
Figure A.7. Reverse flow gas tests on meter A at 50 bar. (Dotted lines represent manufacturer’s meter 
specification.) 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 20 40 60 80 100 120 140 160 180 200
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Nozzle downstream
Nozzle 1.5m upstream
Nozzle 5.5m upstream
 
Figure A.8. Gas tests on meter A at 10 bar with nozzle upstream. (Dotted lines represent 
manufacturer’s meter specification.) 
 12 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Nozzle downstream
Nozzle 1.5m upstream
Nozzle 5.5m upstream
 
Figure A.9. Gas tests on meter A at 30 bar with nozzle upstream. (Dotted lines represent 
manufacturer’s meter specification.) 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700 800 900 1000
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Nozzle downstream
Nozzle 1.5m upstream
Nozzle 5.5m upstream
 
 
Figure A.10. Gas tests on meter A at 50 bar with nozzle upstream. (Dotted lines represent 
manufacturer’s meter specification.) 
 13 
APPENDIX B - METER B RESULTS 
 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700 800
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
 
Figure B.1. Baseline water tests for meter B. (Dotted lines represent manufacturer’s meter 
specification.) 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 20 40 60 80 100 120 140 160 180 200
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Run 1
Run 2
Run 3
 
Figure B.2. Gas tests on meter B at 10 bar. Results shown from different test runs. (Dotted lines 
represent manufacturer’s meter specification.) 
 14 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500
Reference mas flowrate (g/s)
M
et
er
 e
rr
or
 (%
Run 1
Run 2
 
Figure B.3. Gas tests on meter B at 30 bar. Results shown from different test runs. (Dotted lines 
represent manufacturer’s meter specification.) 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700
Reference massflowrate (g/s)
M
et
er
 e
rr
or
 (%
Run 1
Run 2
 
Figure B.4. Gas tests on meter B at 50 bar. Results shown from different test runs. (Dotted lines 
represent manufacturer’s meter specification.) 
 15 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 20 40 60 80 100 120 140 160 180 200
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Forward flow
Reverse flow
 
Figure B.5. Reverse flow gas tests on meter B at 10 bar. (Dotted lines represent manufacturer’s meter 
specification.) 
 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Forward flow
Reverse flow
 
Figure B.6. Reverse flow gas tests on meter B at 30 bar. (Dotted lines represent manufacturer’s meter 
specification.) 
 16 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Forward flow
Reverse flow
 
Figure B.7. Reverse flow gas tests on meter B at 50 bar. (Dotted lines represent manufacturer’s meter 
specification.) 
 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 20 40 60 80 100 120 140 160 180 200
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Nozzle downstream
Nozzle 1.5m upstream
Nozzle 5.5m upstream
 
Figure B.8. Gas tests on meter B at 10 bar with nozzle upstream. (Dotted lines represent 
manufacturer’s meter specification.) 
 17 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Nozzle downstream
Nozzle 1.5m upstream
Nozzle 5.5m upstream
 
Figure B.9. Gas tests on meter B at 30 bar with nozzle upstream. (Dotted lines represent 
manufacturer’s meter specification.) 
 
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500 600 700
Reference mass flowrate (g/s)
M
et
er
 e
rr
or
 (%
Nozzle downstream
Nozzle 1.5m upstream
Nozzle 5.5m upstream
 
Figure B.10. Gas tests on meter B at 50 bar with nozzle upstream. (Dotted lines represent 
manufacturer’s meter specification.) 
 18 
	MAIN MENU
	PREVIOUS MENU
	---------------------------------
	Search CD-ROM
	Search Results
	Print